‘GAME’ CHANGE:The “Red Wedding” is considered the pivotal moment in the entire epic, and it’s due this season. Tobias Menzies (left) plays Edmund Tully, the lucky groom.

‘GAME’ CHANGE: The “Red Wedding” is considered the pivotal moment in the entire epic, and it’s due this season. Tobias Menzies (inset) plays Edmund Tully, the lucky groom. (
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It’s coming.

“Game of Thrones” fans know it’s looming somewhere on the horizon of the HBO show’s upcoming season (Sunday night at 9).

If you’ve never heard of the “Red Wedding,” you will. Fans of author George RR Martin’s fantasy epic consider it the linchpin — a “Game”-changer of epic proportions — of the entire season.

The “Red Wedding” has its own Wikipedia page and scores of Web sites devoted to it.

When it is discussed, die-hard fans don’t even use the full name. It is called simply “the RW.” .

It is so secret HBO officials not only won’t supply photos of the scene or talk about the scene, they refuse to confirm the episode will air this season.

“The ‘Red Wedding’ is a very stressful chapter, and most fans just refer to it as ‘RW’ because . . . when something so wrenching and terrible like this happens, some fans kind of go into denial and say, ‘We’re not even going to deal with this part of the story,’ ” says Tobias McGuffin of winteriscoming.com, a popular site devoted to “Game of Thrones” and Martin’s entire fantasy book series.

“There are major betrayals in the episode . . . and there are a lot of close calls,” McGuffin says.

“A lot of people who are fans of the books want the translation to be as closely hewn as possible . . . they want [the ‘Red Wedding’] to happen exactly as it happened in the book because they love the characters who are involved.”

For the uninitiated, the “Red Wedding” is set around the marriage of Catelyn Stark’s brother, Edmure Tully, to Lady Roslin Frey, a daughter of the powerful Lord Walder Frey.

The wedding is an effort to heal the rift between the two families, which was ignited when Catelyn’s son, Robb Stark — who was betrothed to a member of the Frey clan — ran off and married Jeyne Westerling instead. Big insult.

The “RW” scene has taken on mythic proportions since the books became popular in the mid-1990s.

Even Martin, who’s an executive producer of the HBO series, says he’s “excited and apprehensive” about the “Red Wedding.”

“I think it will have more impact if it takes people unexpectedly,” he told a Web site called omnivoracious.com. “But certainly that’s the scene that both myself and, I think, most of my hardcore fans are looking forward to with a mixture of anticipation and apprehension.”

The chronology of HBO’s “Game of Thrones” has been extremely faithful to Martin’s books, so it figures that the “Red Wedding” episode will probably air toward the end of this season — or even as the season finale.

(A casting notice posted last fall while the series was filming in Northern Ireland — “Seeking LEG ONLY, MALE AMPUTEES” — also seemed a tip-off the scene was being shot for this season. “We understand that this is not for everyone, so please only apply if you are happy to participate,” the ad said.)

“This event is such a key moment and is the event of the third season,” says Elio Garcia, who runs “Thrones” site westeros.org.

“It’s a major turning point for some characters’ story — and it’s really an event that shakes the foundation of some of the players,” Garcia says. “George [RR Martin] completely turned everyone on their head with ‘RW’ in the book and people were massively shocked.

“Part of the story is how [‘Game of Thrones’] gets to ‘RW’ and the journey towards it, but George doesn’t hold back — all the cards are on the table.”

“It’s a visual that is going to stick with people for a long time,” says McGuffin of the “Red Wedding.”

“I hope so,” he says. “I’m not one of those people who fears the ‘Red Wedding’ — I think it’s brilliant storytelling that mixes horror with tragedy.”